Justin Posted June 29, 2014 Share Posted June 29, 2014 And we continue to raise the ceiling.... 18z GFS in northeast/eastern IA at 21z Helicity values over 1200, SBCAPE of 4200 j/kg, and EHI of nearly 29 gfs holy.gif That is a mighty impressive progged sounding. Yikes. However, I am tempering my expectations a bit until tonight gets going and how that evolves. But everyone needs to be paying attention to this potential. This could be a significant outbreak if things come together just right. Link to comment Share on other sites More sharing options...
cyclone77 Posted June 29, 2014 Share Posted June 29, 2014 Most of the convection allowing models show sort of a linear look to the convection tomorrow afternoon/eve, but when you take a closer look you can see supercell looking features along the line. This is the 12z HRW-ARW for around 22z tomorrow. Looks like a line with embedded sups. Still think even this may be a bit too linear considering how much shear there is. Link to comment Share on other sites More sharing options...
Stebo Posted June 29, 2014 Share Posted June 29, 2014 And we continue to raise the ceiling.... 18z GFS in northeast/eastern IA at 21z Helicity values over 1200, SBCAPE of 4200 j/kg, and EHI of nearly 29 gfs holy.gif Wowza, this is just nonsense, I mean EHIs of 10 or more are very noteworthy but one near 30 is unfathomable. Link to comment Share on other sites More sharing options...
Justin Posted June 29, 2014 Share Posted June 29, 2014 I remember when I was a student volunteer at the NWS in the late 90s one late Spring day we had an impressive set up for severe weather coming together with some pretty high helicity values, but when the cumulus started towering they got torn apart. The towers were tilted so much they never got real high in the sky... the atmosphere stayed a loaded gun and never went off. Hopefully we don't see something like that...it is something that will also need to be watched. One thing going against that is the temps and dew's to keep things nice and buoyant. Link to comment Share on other sites More sharing options...
tornadotony Posted June 29, 2014 Share Posted June 29, 2014 Much stronger secondary low on the 18z GFS now too. Link to comment Share on other sites More sharing options...
Stebo Posted June 29, 2014 Share Posted June 29, 2014 If this latest trend of a strong secondary low forming in the region comes to fruition, the ceiling of this potential flies through the roof. I mean we are going to have an extraordinary response in the low and mid level wind fields with areas around 5000 J/kg SBCAPE. Link to comment Share on other sites More sharing options...
tornadotony Posted June 29, 2014 Share Posted June 29, 2014 I remember when I was a student volunteer at the NWS in the late 90s one late Spring day we had an impressive set up for severe weather coming together with some pretty high helicity values, but when the cumulus started towering they got torn apart. The towers were tilted so much they never got real high in the sky... the atmosphere stayed a loaded gun and never went off. Hopefully we don't see something like that...it is something that will also need to be watched. One thing going against that is the temps and dew's to keep things nice and buoyant. There is absolutely 0% chance of that happening if CAPE is 4200 J/kg. Hell there's little chance of that if CAPE is 3000 J/kg. Link to comment Share on other sites More sharing options...
MCS_hunter Posted June 29, 2014 Share Posted June 29, 2014 I have a friend that lives in Cedar Rapids and she is terrified of severe weather. I'll try to keep her informed as best as I can while I'm at work. 18z GFS is absolutely insane with the parameters maxing out over a decently sized area. Link to comment Share on other sites More sharing options...
Thundersnow12 Posted June 29, 2014 Author Share Posted June 29, 2014 What keeps worrying me as chasing will be the storm motions. Just have to hope you have a good view somewhere. Link to comment Share on other sites More sharing options...
Stebo Posted June 29, 2014 Share Posted June 29, 2014 Another thing to note with a strong secondary low the attendant shear associated with this low would help to maintain supercells and considering the wind fields associated with the low the atmosphere should remain buoyant well into the evening and potentially overnight. Link to comment Share on other sites More sharing options...
nwburbschaser Posted June 29, 2014 Share Posted June 29, 2014 What keeps worrying me as chasing will be the storm motions. Just have to hope you have a good view somewhere. I was thinking about that and it really brings into question how far west that you'd really want to get. I'm really not sure that I want to get west of the Mississippi unless that's the only play just because crossing back over could be such a challenge depending where you would end up. I'll obviously work those details out in the morning, but things could be somewhat difficult in the E IA/NW IL area from a terrain standpoint. Link to comment Share on other sites More sharing options...
cyclone77 Posted June 29, 2014 Share Posted June 29, 2014 Amazing sounding/hodo porn on the 18z GFS. This is the hodo for eastern IA to go along with Thundersnow's sounding. Just sick. Don't see this associated with nearly 5000j/kg cape very often. Link to comment Share on other sites More sharing options...
A-L-E-K Posted June 29, 2014 Share Posted June 29, 2014 E. IA, far NW IL and much of SW WI look pretty locked and loaded for super cells producing large tornados barring any major mesoscale debris issues which is looking increasingly unlikely. Link to comment Share on other sites More sharing options...
MCS_hunter Posted June 29, 2014 Share Posted June 29, 2014 Should we expect an upgrade to High Risk? Link to comment Share on other sites More sharing options...
andyhb Posted June 29, 2014 Share Posted June 29, 2014 Should we expect an upgrade to High Risk? If supercells are expected to be dominant for any length of time (which is looking more and more possible), there's a good chance. Link to comment Share on other sites More sharing options...
Thundersnow12 Posted June 29, 2014 Author Share Posted June 29, 2014 Should we expect an upgrade to High Risk? It's a lock to be a MDT Link to comment Share on other sites More sharing options...
Central Illinois Posted June 29, 2014 Share Posted June 29, 2014 Should we expect an upgrade to High Risk?We don't even have a moderate yet..... Link to comment Share on other sites More sharing options...
A-L-E-K Posted June 29, 2014 Share Posted June 29, 2014 We don't even have a moderate yet..... pretty much but yeah, at least E. IA, NW IL, and SW WI looks like a lock for mod…i'm unsure how things evolve further east. Link to comment Share on other sites More sharing options...
Central Illinois Posted June 29, 2014 Share Posted June 29, 2014 pretty much but yeah, at least E. IA, NW IL, and SW WI looks like a lock for mod…i'm unsure how things evolve further east. Yeah I agree we will probably see a pretty big Moderate risk in the next update. Link to comment Share on other sites More sharing options...
MCS_hunter Posted June 29, 2014 Share Posted June 29, 2014 The high end Slight was mainly due to the concern of how today unfolded... Link to comment Share on other sites More sharing options...
tornadotony Posted June 29, 2014 Share Posted June 29, 2014 Seriously we're looking at one of the most potent thermodynamics and kinematics combinations likely ever modeled by a computer and we have a "hype" problem? Hahahahahahahahahahahahahahahahahahahahahahahahahahahaha. Yeah, there are questions about storm mode perhaps, but for pete's sake, come on. Even the more "subdued" NAM has 0-3 km EHIs in the 8-10 range. Seriously. Link to comment Share on other sites More sharing options...
Central Illinois Posted June 29, 2014 Share Posted June 29, 2014 The high end Slight was mainly due to the concern of how today unfolded...If the Midwest is mostly clear tomorrow morning I do think we could see some strong wording from the spc and local nws (DVN/LOT/ILX/MKX)ILX did talk it up a little more this afternoon then what they did this morning so it's a start. Link to comment Share on other sites More sharing options...
tornadotony Posted June 29, 2014 Share Posted June 29, 2014 It isn't like we went into Paint and drew out those fcst soundings and labeled them hype. My gosh. Some of these forecast soundings are so ridiculous that I wouldn't even go that far if I were making a dream fantasy hype sounding. Link to comment Share on other sites More sharing options...
Hoosier Posted June 29, 2014 Share Posted June 29, 2014 18z GFS actually has a small area of 850 mb winds of 70 kts tomorrow evening. I don't think anybody's really been hyping. Nobody is calling for the worst outbreak ever or something along those lines. Just in the abstract, when you have shear more along the lines of what you'd see in spring combined with summertime instability, it increases the chances of something bad happening. Link to comment Share on other sites More sharing options...
A-L-E-K Posted June 29, 2014 Share Posted June 29, 2014 IA finally popping off, should push through here in the early am Link to comment Share on other sites More sharing options...
Tim from Springfield (IL) Posted June 29, 2014 Share Posted June 29, 2014 Just curious, although I'm not an expert on this--how would tomorrow's severe threat compare to two derecho events that occured on this week in history in parts of this subforum: 7/4-5/80 and 6/29/98? I would have been only 3 years old at that time, but I have heard that 7/4/80 dewpoints in parts of central Illinois before the storm were near (if not even over) 80 degrees. 6/29/98 is the one at the top of my head when I'm thinking of tomorrow's threat (not just the fact that it occurred 16 years ago today), considering the area at risk and the heat/unsettled weather which preceded that event. I was wondering about if there's any model similarities between these two events and what might transpire tomorrow. http://www.spc.noaa.gov/misc/AbtDerechos/casepages/jul4-51980page.htm http://www.spc.noaa.gov/misc/AbtDerechos/casepages/jun291998page.htm Link to comment Share on other sites More sharing options...
andyhb Posted June 30, 2014 Share Posted June 30, 2014 Convection definitely picking up across IA now, got a tornado warning SE of Ft. Dodge. Currently fairly discrete, although we'll see if upscale growth occurs with strengthening low level winds into the later evening.. Link to comment Share on other sites More sharing options...
MCS_hunter Posted June 30, 2014 Share Posted June 30, 2014 Convection definitely picking up across IA now, got a tornado warning SE of Ft. Dodge. Currently fairly discrete, although we'll see if upscale growth occurs with strengthening low level winds into the later evening.. I can see the tornado-warned storm all the way from my house in central MN. Link to comment Share on other sites More sharing options...
tornadotony Posted June 30, 2014 Share Posted June 30, 2014 Hurricane crossing the Mississippi River tomorrow evening on the 18z 4-km NAM. Link to comment Share on other sites More sharing options...
David Reimer Posted June 30, 2014 Share Posted June 30, 2014 Hurricane crossing the Mississippi River tomorrow evening on the 18z 4-km NAM. nam-hires_namer_033_sim_reflectivity.gif Indeed! Two hours later it slams Chicago with 70-80 MPH winds with an impressive simulated structure. I definitely am happy I don't have to fly in/out of O'hare tomorrow evening. Link to comment Share on other sites More sharing options...
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